Self-propelling projectile



April 23, 1946. w. w. FARR SELF-PROPELLING PROJECTILE Filed Dec. 27, 1943v INVENToR Will om WSF cm.

BY ATTORNEY Patented Apr. -23, 1946 SELF-PROPELLING IPROJECTILE William W. Farr, Grosse Pointe Park. Mich., as-

signor, by mesiie assignments, to United States of America Application December 2,7. 1943, Serial 4 Claims.

This invention relates to rocket-propelled devices, more particularly to the casing for the propelling charge.

The primary object of the present invention is to provide a rocket-propelled device of the multi-jet type in which the jets are "formed through a novel arrangement of parts sofconstructed as to provide for convenient and simple machining and assembly operations. y

Another object is to provide a multi-jet rocket-propelled device of new and improved construction wherein the jets are formed by interfltting tubular parts so 'shaped yas to provide for desired concentricity of the jet walls.

A further object is to provide an improved rocket-propelled device with a plurality of axially-spaced jets so constructed as to insure true night of the device.

With the foregoing and other objects in view which will be apparent, 'from the following detailed description, to those skilled in the art to which the invention appertains, the present invention consists in certain features of construction and combinations of parts to be hereinafter described with reference to the accompanying drawing, and then claimed.

In the drawing,

Figure 1 is a longitudinal view of a rocketpropelleddevice incorporating the features of the present invention;

Figure 2 is an enlarged longitudinal section through the trailing rocket portion of the device of Figure 1;

Figure 3 isa transverse section taken substantially on line 3-3 of Figure 2; and

Figure 4 is a fragmentary section of a modi'- fled construction.

Referring to the accompanying drawing, the present invention is applicable to various types of rocket-propelled devices, such as for example. an explosive projectile, chemical projectiles or flare projectiles, and to this end the projectile or other decise is merely indicated in outline by the numeral 5 in Figure 1. tion is directed to the rocket portion 6 which is attached to the trailing end of the projectile or other device 5.

The rocket portion 6 of the present invention is comprised mainly of an inner tubular member 1 open at its ends, a plurality of outer tubular elements comprising a leading end element 8, intermediate elements 9 and a trailing end element III, and a stabilizing member II.

The opposite ends of the tubular member 1 The present invenare internally threaded at I2 and I3 for threaded attachment at the forward end to the main projectile or other device E and for threaded reception at the rearward end of the stabilizing member II. Depending upon the number of jets or Venturi passages desired, the tubular member is provided at axially spaced zones with a series of openings I4 extending through the wall thereof. As shown here, there are three such groups of axially spaced openings I4 for association with three Venturi passages to be later described.

Each jet or Venturi passage I5 is formed by the ends of adjacent tubular elements-the forward passage I5 between the adjacent ends of the forward element 8 and the forward intermediate element 9, the intermediate passage I5 between the adjacent ends of the intermediate elements 9, and the rearward passage` I5 between the adjacent ends of the rearward intermediate element 9 and the rearward element III.

Each of-these tubular elements is of .such diameter as to have a slidable yet tight fit with the tubular member 1, the end elements 8 and I0 having inturned flanges I6 and II, respectively, which in the assembly engage with the ends of the tubular member 1, as shown in Figure 2.

The forward end of each of the tubular elements 9 and I0 terminates adjacent a group of openings I4 and while being tapered toward such end to provide one wall I8 of the Venturi passage I5 is formed with lradially outwardly extending. circumferentially spaced vanes I9 which extend longitudinally for an appreciable distance.

The inner wall of the rearward end of each of the elements 8 and 9 iiares outwardly in tapering fashion at a slightly'greater angle than the wall I8 of the adjacent element to form the outer wall 20 of the Venturi passage I5, the circumferential faces of the vanes I9 of the adjacent element having the same taper as the wall 20 so that rearward and forward ends of adjacent elements substantially nest within the other through engagement between the circumferential faces of the vanes I9 and the Venturi walls The portion of each wall 2li which overlies or surrounds the openings I4 is 'circumferentially i, recessed or' enlarged at 2l to provide a circumferential distributing passage.

The stabilizing element Il comprises an assemblage of stabilizing iins 22 mounted within a surrounding metal band 23 and having their forward ends secured to a plug 24 having threaded engagement with the threads I3 at the rearward end of the tubular member 1. The plug 24 is annular in cross section and threadably receives at its forward end a rod member 25 upon which the propelling charge 26 is mounted;

The rod 25 near its attachment to the plug 24 is provided with a cross passage 21 and an axial passage 28 opening into the bore of the plugr for ignition of the propelling charge from a flash charge (not shown) contained in the plug bore. The outer end of the plug bore is closed by a threaded member 29 having a series of openings 30 therethrough for the reception of ignition wires (not shown) used in igniting the flash charge.

Various forms of the propelling charge may be utilized and as here partially shown in solid and dotted outline, the charge may comprise a series of blocks 3I separated by spacers 32 mounted on the rod 25 throughout its length, the forward end of the rod 25 having a headed portion 33 for retaining the blocks 3i on the rod 25.

In the assembly of the structure described, first the intermediate elements 9 and then the end elements 8 and IDMare forced on the tubular member I and then the stabilizer assembly II is threaded into the rearward end uf the member l, the flanged portion 34 thereof forcing the flanged end of the rearward element firmly against the end of the member l.

Prior to assembly of the stabilizing element II to the member l, the rod 25 having the propelling charge of blocks 3i thereon may be secured to the plug 24, or this may be accomplished after the stabilizer element H is assembled.

When the structure described and so assembled is attached through the medium of the threads I2 at the forward end of member 1 to the projectile or other device 5, the liange I6 of the forward element 8 is securely clamped against the forward end of member l, the lengths of the elements B, 9 and I0 being such that during this operation these elements are forced into tight-fitting end engagement.

inasmuch as the means for initially igniting the propelling charge forms no part of the present invention, the same is not shown.

If desired, the varies I9 instead of being truly axial may be angularly arranged so that the Igases resulting from the burning propelling charge which discharge through the openings It and thence through the Venturi passages I5 under pressure may tend to cause rotation of the structure at the initiation of the ight of the same.

Also. if desired, the vanes I3 may be formed on the walls 2Il`instead of the walls I8.

The modified construction of Figure 4 is similar to the construction desoribedexcept thatthe forward and rearward end portions of the tubular elements previously described are formed as separate elements. As will be seen from Figure 4, two separate ring or sleeve elements 4I) and 4I are employed to form each Venturi passage I5, the sleeve element Ill forming the outer Wall I9 of the passage and the sleeve element 4I forming the inner wall I8 of the passage. The sleeve element 4I of one passage is separated from the sleeve element of the next adjacent passage by a tubular spacer 42. One advantage of this modied construction resides in the iact that tubular stock may be used for the spacers 42.

The structures described, as is obvious from the foregoing description. are capable of easy assembly. Also, by reason of -the concentricity of the parts, such parts, except for the formation of the vanes I9, may be machined by turning operations with the result that the same can be properly balanced whereby to insure true and accurate iilght.

It will be apparent that various changes may be made in the detailed arrangements and construction of the parts described without departing from the spirit and substance of the present invention, the scope o1 which is defined by the appended claims.

What is claimed is:

1. In a rocket-propelled device having a pro- `peiling charge, a tubular casing surrounding the propelling charge, said charge when red being adapted to build up propelling pressures within said casing, and annularsleeve elements each having a portion closely fitting the external surface of said casing, said portions being spaced apart axially of said casing, one of said elements overlapping both the space between said portions and the other element in circumferentially spaced relation and defining with said other element an exhaust jet communicating with the space defined by said closely fitting portions and the overlapping part of said one element, said casing having at least one aperture through the wall thereof opening into said space, said elements having interengaging parts for preventing relative axial movement of said elements toward each other.

2. In a rocket-propelled device having a propelling charge,.a tubular casing surrounding the propelling charge, said charge when fired being adapted to build up propelling pressures within said casing, and annular sleeve elements each having a portion closely fitting the external surface of said casing, said portions being spaced apart axially of said casing, one of said' elements overlapping both the space between said portions and the other element in circumferentially spaced relation and defining with said other element an exhaust jet communicating with the space defined by said closely fitting portions and the overlapping part of said one element, said casing having at least one aperture through the wall thereof opening into said space, the `iet dening surface of one of said elements having a plurality of integral radial vanes engaging the jet defining surface of the other of said elements.

3. In a rocket-propelled device having a propelling charge, a tubular casing surrounding said charge, said charge being adapted when fired to develop propelling pressures within said casing, and means providing a plurality of axially spaced .iets for the passage under pressure of gases de- Veloped within the casing by the propelling charge, said means comprising axially spaced groups of apertures in the wall of said casing and a plurality of sleeve elements closely fitting around said casing, the end portions of adjacent elements overlapping each other in circumferentially spaced relation, the inner overlapped end portion of each element terminating at least in part at one side of a group of apertures and the outer overlapped end portion of each element circumferentially spanning a group of apertures to provide a surrounding chamber communicating with the interior of the casing through the group of apertures and with the space defined by said circumferentially overlapped end portions.

4. In a rocket-propelled device having a propeiling charge, a tubular casing surrounding said charge, said charge being adapted when fired to develop propelling pressures within said casing,

cumferentially spanning a group of apertures to provides. surrounding chamber communicating with the interior of the casing through the group of apertures and with the space defined by said clrcumferentially overlapped end portions, the overlapping end portions having a plurality of circumferentially spaced vanes extending between the opposed walls thereof, said vanes being an integral part of one of said opposed Walls and l0 engaging the other of said walls. f

W. FARR. 

